The Xfce development team is pleased to announce that the first release candiate of Xfce 4.4 is now available for download. A lot of bugs were fixed during the last two months and several new features were added. For example the brand new Xarchiver 0.4.0 is included, trash support was added to Thunar and xfdesktop, and the overall memory usage was reduced. See the ChangeLog for a complete list.

I agree with you that tabs would be a nice feature for Thunar. I like the way Thunar is nice and simple and fast right now. It would be great to be able to switch tabs without opening several thunar windows.

just for your information, perhaps you might try the pcman file manager (look for it in gnome files, but I think it is something like http://pcmanfm.sf.net). It has a Thunar-like interface, with Tabs. Last time I checked it missed some Thunar's features, though.